Drug dispenser

ABSTRACT

A drug dispenser ( 1 ) has a hollow body ( 2 ) with a housing ( 6 ) for a pressurised can ( 7 ) containing a drug and its propellant arranged on top of the body. The can has an outlet stem ( 8 ) received in a socket ( 9 ) in an internal spigot ( 10 ). This has a junction with a flexible tube ( 11 ), leading to a kink valve pair ( 12, 14 ). The tube continues on to a second internal spigot ( 15 ), having a spray nozzle ( 16 ) just within a breathing opening ( 5 ). The kink valve pair ( 12, 14 ) is formed as a moulding of the tube, with side wings ( 17 ). Towards the ends of the wings, they have thinner portions ( 17.1 ) at which there are apertures ( 18 ) immediately adjacent the tube. The arrangement, which is similar to that in my International Application No. PCT/GB01/03313, defines positions at which the tube kinks to close its through bore ( 19 ). The thinner portions are provided in two positions, which provide the two kink valves. An intermediate section ( 20 ) of the tube, with a predetermined volume is provided between the kink valves. At the intermediate section, the tube ( 11 ) is clipped to flap ( 21 ), pivoted at its end ( 22 ) to the side wall of the body. As a patient breathes through the device, the flap is moved by the action of the breath on it. Specifically, as the patient inhales, the flap moves towards the breathing opening and as the patient exhales the flap moves towards the ambient opening. The flap has clearance with the passage such that it does not significantly obstruct the air passage, but at the same time the inhalation and exhalation positively moves the flap. The kink valve pair moves with the flap.

[0001] The present invention relates to a dispenser for dispensing drugsin small breathable particles.

[0002] Increasingly drugs are dispensed as a mist for inhalation. Notonly is this used for asthma drugs, but it is used for other drugs aswell. Asthma drugs have been dispensed by a nebuliser, which provides amist for inhalation by successive breaths. Increasingly, nebulisers arebeing replaced by pressurised metered dose inhalers. The former arebulky, expensive pieces of equipment, whilst the latter are disposableaerosol devices but they suffer from some disadvantages. In particular,inhalers require a deep breath to ensure that the medicament is carriedinto the lungs. Patients, in particular infants, young children andthose with severe symptoms, having weak breathing may be unable to usean inhaler effectively and have to rely on a nebuliser.

[0003] Conventionally aerosol storage devices have utilised a metal canfor storage of the contents to be dispensed under pressure contained inthe can. However, it is anticipated that in future metallic cans may bereplaced by cans of plastics material or even of glass for specialisedapplications. Accordingly as used herein the term “can” means not onlymetallic cans but substitute or equivalent containers of othermaterials, in particular glass and plastics materials.

[0004] The object of the invention is to provide an improved breathableparticle drug dispenser, which utilises aerosol pressure for dispersionof the drug yet which is not limited to dispensing metered doses betweenwhich the aerosol storage device requires manual actuation to release ametered dose.

[0005] According to a first aspect of the invention there is provided adrug dispensing device for repetitive dispensing on inhalation of a drugreleased from a pressurised drug source with a can body and a deliverystem, the dispenser comprising:

[0006] a hollow body having:

[0007] a wall enclosing a breath passage within the hollow body,

[0008] an ambient opening to the breath passage,

[0009] a patient breathing opening to the breath passage,

[0010] a can receptor attached to the hollow body for accommodating thecan of the pressurised drug source,

[0011] a junction member attached to the hollow body for connection withthe dispensing stem of the pressurised drug source and leading delivereddrug from the dispensing stem,

[0012] a drug disperser for dispersing the delivered drug towards thepatient breathing opening,

[0013] a drug duct from the junction member to the drug disperser,

[0014] a breath detector arranged in the breath passage to be acted onby breath passing therethrough, and

[0015] dose release means operatively connected to the breath detector,the dose release means being so arranged that:

[0016] on inhalation, with the breath detection member detecting such, adose is released into the drug duct and dispersed from the drugdisperser in the patient breathing opening;

[0017] the arrangement permitting a small dose of the drug to berepetitively released on each breath by the patient.

[0018] According to a second aspect of the invention there is provided adrug dispensing device for repetitive dispensing on inhalation of a drugreleased from a pressurised drug source with a can body and a deliverystem, the dispenser comprising:

[0019] a hollow body having:

[0020] a wall enclosing a breath passage within the hollow body,

[0021] an ambient opening to the breath passage,

[0022] a patient breathing opening to the breath passage,

[0023] a can receptor attached to the hollow body for accommodating thecan of the pressurised drug source,

[0024] a junction member attached to the hollow body for connection withthe dispensing stem of the pressurised drug source and leading delivereddrug from the dispensing stem,

[0025] a drug disperser for dispersing the delivered drug towards thepatient breathing opening,

[0026] a drug duct from the junction member to the drug disperser, and

[0027] a valve in the drug path from the container to the disperser,

[0028] a valve actuator operatively connected to the valve and includinga breath detection member arranged in the breath passage to be acted onby breath passing therethrough,

[0029] the valve and the actuator being so arranged that:

[0030] on inhalation, with the breath detection member detecting such,the valve is opened to allow pressurised drug through a downstreamportion of the drug duct and disperse from the drug disperser in thepatient breathing opening breathing adapter;

[0031] the arrangement permitting a small dose of the drug to berepetitively released on each breath by the patient.

[0032] In one series of embodiments, the valve will be a dual in linevalve arrangement, the arrangement having:

[0033] an upstream valve,

[0034] a downstream valve and

[0035] an intermediate section of the drug duct between the two valves,the valve and the actuator being so arranged that:

[0036] on inhalation, with the breath detection member detecting such,the downstream valve is opened to allow pressurised drug in the saidintermediate section to pass through a downstream portion of the drugduct and disperse from the drug disperser in the patient breathingopening and

[0037] subsequently the upstream valve is opened to allow pressuriseddrug to pass from an upstream portion of the drug duct into theintermediate section;

[0038] the arrangement permitting a small dose of the drug metered bythe intermediate section to be repetitively released therefrom on eachbreath by the patient.

[0039] Particularly where, as described below, the dual in line valvearrangement is mechanically actuated by action of breath on a flap orpiston, it is on exhalation, with the breath detection member detectingsuch, that the upstream valve is opened for passage of the pressuriseddrug into the intermediate section.

[0040] Alternatively, and particularly where, as also described below,the dual in line valve arrangement is electrically operated via breathdetection by a transducer, it is during the inhalation or during overlapbetween inhalation and exhalation, that the upstream valve is opened forpassage of the pressurised drug into the intermediate section.

[0041] Conveniently, the intermediate section of the drug duct will havea predetermined metering volume.

[0042] Preferably, the up- and down-stream valves are mechanicallylinked together, with one being closed when the other is open and viceversa; and usually the valves will be adapted to be both closed togetherin a mid-position of their mechanical linkage.

[0043] Alternatively to the series of embodiments having two valves, asingle valve can be employed with the valve actuator includes means forclosing the valve a predetermined time after its opening on inhalation,the arrangement being such that the predetermined dose of drug isreleased during the predetermined period under pressure from drug source

[0044] Normally the device will include a breathing adapter at thepatient breathing opening for guiding the delivered drug to a patient'sairway, and the breathing adapter will be one of a group comprising amouthpiece, a face mask, an adapter for a mouthpiece, an adapter for aface mask or a spacer chamber.

[0045] In a two valve embodiment, the up- and down-stream valves can beelectro-magnetic valves and the breath detection member can be atransducer arranged in the breath passage. Also in the single valveembodiment, the valve can be an electro-mechanical valve, with thebreath detection member being a transducer arranged in the breathpassage and the valve actuator including a control circuit adapted andarranged to open the valve for a predetermined period on detection ofinhalation and then to close the valve.

[0046] The transducer can be a pressure transducer, detecting inhalationby fall in static pressure or increase in dynamic pressure (velocityhead) on the ambient side of the transducer (or fall of dynamic pressureon the breathing adapter side) and exhalation by increase in staticpressure decrease in dynamic pressure on the ambient side of thetransducer (or increase of dynamic pressure on the breathing adapterside). Again, the transducer can be a flow meter having a member movablein the direction of flow through the tube. However, it is preferably atemperature transducer, detecting inhalation by fall in temperature andexhalation by increase in temperature. Conveniently a counter isarranged to be incremented by successive indications of breaths given bythe transducer for counting the number of breaths and drug dispersalscontrolled by the valve arrangement.

[0047] In other embodiments, the up- and down-stream valves aremechanical valves and the breath detection member is a movable flap or aslidably mounted piston arranged in the breath passage to be moved inaccordance with breath past it and linked to the valves for theiractuation.

[0048] Preferably, the breath detecting flap is a pivotally mounted tobe movable by the patient's breathing between an inhalation position andan exhalation position and the valves—or their actuation members—arepivotally operated, the flap and the valves or their actuation membersbeing connected together to open the upstream valve (the downstreamvalve being closed) on exhalation and movement of the flap away from thebreathing adapter to fill the intermediate section with drug and openingthe downstream valve (the upstream valve being closed) on inhalation andmovement of the flap towards the breathing adapter to dispense the drug.

[0049] Whereas variants can be envisaged, such as the use of a doublepinch valve in a rocker format or other rocker valves; in the preferredembodiments, the valves are kink valves, that is to say valves havingflexible tubes which are arranged to kink to close the valve and un-kinkto open the valve.

[0050] In one embodiment, the up- and down-stream portions of the drugduct are arranged to connect to the respectively opposite ends of theintermediate section via the kink valves, the said portions both beingto the same side of the intermediate section and describing a squat Δtherewith, and the intermediate section being connected directly to theflap for movement along the breath passage with the flap.

[0051] In another embodiment, the up- and down-stream portions of thedrug duct are arranged to connect to the respectively opposite ends ofthe intermediate section via the kink valves, the said portions being onopposite sides of the intermediate section and describing a Z therewith,and the intermediate section being crankedly connected to the flap formovement transversely of the breath passage with movement of the flaptherealong.

[0052] Preferably, the drug duct has a volume between the junctionmember and the valve corresponding to a plurality of the doses releasedon a plurality of inhalations for use with multiple doses from a metereddose pressurised drug source, whereby such plural depressions chargesthe duct with a determined quantity of drug for a plurality ofinhalations.

[0053] According to another aspect of the invention, a drug dispensercomprises a dispensing device of the first aspect in combination with apressurised drug source, the can body being accommodated in the housingand the delivery stem connected to the junction member.

[0054] It is envisaged that the dose released per breath may beadjustable, by adjusting the metering volume of the intermediate sectionof the drug duct.

[0055] Normally the container will be provided with a release valvewhereby dispensing of the drug can be stopped and started at will.However, the container may be a metered dose container.

[0056] According to a further embodiment, there is provided A drugdispensing device for repetitive dispensing on inhalation of a drugreleased from a pressurised drug source with a can body, metered doserelease drug release valve and a delivery stem, the dispensercomprising:

[0057] a hollow body having:

[0058] a wall enclosing a breath passage within the hollow body,

[0059] an ambient opening to the breath passage,

[0060] a patient breathing opening to the breath passage,

[0061] a can receptor attached to the hollow body for accommodating thecan of the pressurised drug source,

[0062] a junction member attached to the hollow body for connection withthe dispensing stem of the pressurised drug source and leading delivereddrug from the dispensing stem,

[0063] a drug disperser for dispersing the delivered drug towards thepatient breathing opening,

[0064] a drug duct from the junction member to the drug disperser, and

[0065] a breath detection transducer arranged in the breath passage tobe acted on by breath passing therethrough,

[0066] a can actuator operatively connected to the body for moving thecan towards the junction member,

[0067] the can actuator being so arranged that:

[0068] on inhalation, with the breath detection member detecting such,the can is moved to operate its metered dose valve for allowingpressurised drug to flow to the drug disperser and to disperse from thedrug disperser in the patient breathing opening;

[0069] the arrangement permitting a small dose of the drug to berepetitively released on each breath by the patient.

[0070] To help understanding of the invention, a specific embodimentthereof will now be described by way of example and with reference tothe accompanying drawings, in which:

[0071]FIG. 1 is a cross-sectional side view of a dispenser according tothe invention;

[0072]FIG. 2 is a scrap, plan cross-sectional view of a kink valveportion of a drug duct of the dispenser of FIG. 1;

[0073]FIG. 3 is a scrap cross-sectional side view of the kink valveportion of the drug duct, with both valves closed;

[0074]FIG. 4 is a view similar to FIG. 3 with a flap displaced oninhalation, the downstream valve open for drug release and the upstreamvalve closed;

[0075]FIG. 5 is a view similar to FIG. 1 of a second dispenser accordingthe invention;

[0076]FIG. 6 is a view similar to FIG. 4 of the second dispenser;

[0077]FIG. 7 is a view similar to FIG. 5 of the second dispenser;

[0078]FIG. 8 is a cross-sectional end view on the line VIII-VIII of thesecond dispenser;

[0079]FIG. 9 is a diagrammatic side view of the second dispenser withalternative patient adapters;

[0080]FIG. 10 is a view similar to FIG. 5 of a third dispenser accordingto the invention;

[0081]FIG. 11 is a view similar to FIG. 5 of a fourth dispenseraccording to the invention;

[0082]FIG. 12 is a view similar to FIG. 5 of a fifth dispenser accordingto the invention; and

[0083]FIG. 13 is a side view of a valve variant for the dispenser ofFIG. 1.

[0084] Referring to FIGS. 1 to 4, the drug dispenser 1 has a hollow body2 providing a breath passage 3, with an ambient opening 4 and a patientbreathing opening 5. A housing 6 for receving a pressurised can 7containing a drug and its propellant is arranged on top of the body. Thecan has an outlet stem 8 received in a socket 9 in an internal spigot10. This has ajunction with a flexible tube 11, leading to a kink valvepair 12,14. The tube continues on to a second internal spigot 15, havinga spray nozzle 16 just within the breathing opening 5.

[0085] The kink valve pair 12, 14 is formed as a moulding of the tube,with side wings 17. Towards the ends of the wings, they have thinnerportions 17.1 at which there are apertures 18 immediately adjacent thetube. The arrangement, which is similar to that in my InternationalApplication No. PCT/GB01/03313, defines positions at which the tubekinks to close its through bore 19. The thinner portions are provided intwo positions, which provide the two kink valves. An intermediatesection 20 of the tube, with a predetermined volume is provided betweenthe kink valves.

[0086] At the intermediate section, the tube 11 is clipped to flap 21,pivoted at its end 22 to the side wall of the body. As a patientbreathes through the device, the flap is moved by the action of thebreath on it. Specifically, as the patient inhales, the flap movestowards the breathing opening and as the patient exhales the flap movestowards the ambient opening. The flap has clearance with the passagesuch that it does not significantly obstruct the air passage, but at thesame time the inhalation and exhalation positively moves the flap. Thekink valve pair moves with the flap.

[0087] Referring to FIG. 4, the inhalation action is shown. The air tobe breathed in moves in the direction of the arrow B and the flap isdrawn along with it. The intermediate section 20 is tilted, moving thevalve 12 down to the pivot side of the passage. This action tightens thelength of tube 12.1 leading back to the junction with the can. Thiscauses the upstream kink valve to tighten and remain closed. The downstream kink valve 14 moves closer to the spray nozzle 16. The length oftube 14.1 between these two is slackened, causing the kink valve 14 tostraighten somewhat and open. Thus the drug and pressurised propellantwithin the intermediate section 20 is released.

[0088] On exhalation, the flap 21 is moved back in the oppositiondirection to that shown in FIG. 4, closing the downstream valve 14 andopening the upstream valve 12. Thus pressurised propellant and drug inthe upstream portion 12.1 of the tube is able to pass into theintermediate section, for dispensing when the cycle is repeated.

[0089] To charge the upstream tube portion 12.1 in the first instance,the can is depressed. Where it has a metered dose release valve, aprescribed number of depression and releases will release a knownquantity of the drug into the tube. Successive breathing through thetube will then steadily dispense the drug. Normally the device will beused for a number of breaths exceeding the theoretical numbercorresponding to the quantity of drug released, to ensure that theupstream tube is completely emptied.

[0090] Where the known quantity of drug to be dispensed is large incomparison with the volume of the normal upstream tube portion, thisvolume can be increased by use of a larger diameter tube for part of itslength. The device can be designed with the upstream tube volume beingdefined, whereby it completely fills with the required dose. Thusfilling of the tube with an excess number of depressions of the can, asopposed to use of a determined number of depressions, can be used torelease from the can the prescribed dosage to be inhaled.

[0091] It will be appreciated that the two kink valves are mechanicallylinked, with one being closed when the other is open and vice versa. Atno time are both valves open together and indeed both are closed whenthe valve arrangement is in mid-position.

[0092] Turning on to FIGS. 5 to 8, the dispenser 101 there shown differsas regards it kink valve arrangement and the arrangement for releasingthe drug. The dispenser body 102 has:

[0093] a breath passage 103,

[0094] an ambient opening 104,

[0095] a patient breathing opening 105,

[0096] a can housing 106,

[0097] a drug can 107,

[0098] a can outlet 108,

[0099] a socket 109 & internal spigot 110,

[0100] a flexible tube 111 with an upstream portion 112.1 & and adownstream portion 114.1,

[0101] a kink valve pair 112,114,

[0102] a second internal spigot 115 & spray nozzle 116

[0103] tube side wings 117, thinner portions 117.1 and apertures 118

[0104] a through bore 119 and a tube intermediate section 120 and

[0105] an end 122 pivoted flap 121.

[0106] These features have direct equivalents with the similarlynumbered features in the first embodiment.

[0107] However the flap and kink valves are differently arranged. Theflap is pivoted at a position spaced from the side of the breath passage103 and carries an crank 121.1 which extends along the breath passage.At its distal end, the crank is pivotally connected to a Y piece 121.2,itself pivotally connected to trunnions 117.1 on the intermediate tubesection 120. The arrangement is such that at rest (FIG. 6) both kinkvalves 112,114 are closed. On inhalation (FIG. 7), the intermediatesection 120 is lifted and turned slightly anti-clockwise as the upstreamportion 112.1 tightens. This keeps the upstream valve 112 closed, butopens the downstream valve 114. The drug is dispensed via the spraynozzle 116 from the intermediate section 120. Similarly exhalationallows recharging of the intermediate section from the upstream tubeportion 112.1.

[0108] The arrangement for charging the upstream tube portion differs inthat the can is a non-metered dose can. A release lever 131 is pivotedto the can housing 106, with an abutment area 132 contacting the can anda handle 133 extending over the central region 134 of the body 102.Gripping of the dispenser can be such that the handle is depressed torelease drug and propellant continuously into the upstream tube portion.However, since one or other (or both) of the kink valves 112,114 isalways closed, the drug is released only on inhalation. The prescribeddose can be inhaled by keeping the handle depressed for a specificnumber of breaths, which dispense a specific quantity of drug,corresponding to the volume of the intermediate section times the numberof inhalations. As with the first embodiment, the upstream portion ofthe tube can be emptied of drug by continued breathing through thedevice after release of the handle 133.

[0109] Turning to FIG. 9, the second dispenser—and indeed the first—willnormally be used in conjunction with a mouthpiece M or a facemask F or aspacer S or an adapter A for any of these. These fit the body 102 at theopening 105 and are provided for positively guiding the delivered drugto a patient's airway.

[0110] Turning now to FIG. 10, an electronic version of the secondembodiment is shown. In place of kink valves, it has two electromagneticvalves 212, 214. In place of the flap its has a temperature transducer221, typically a thermocouple. These three are connected to a controlcircuit 241, powered by a cell 242 and having a counter associated withit. The temperature of the transducer falls with inhalation and riseswith exhalation. This can be utilised to program the control circuit toopen the downstream valve 214 only on inhalation and open the upstreamvalve 212 only on exhalation. Alternatively, bearing in mind the abilityto meter a dose by timing, as described in respect of FIG. 11 below, thedownstream valve 214 can be opened and closed again during the sameinhalation and indeed the upstream valve opened and closed again tocharge the intermediate section also during the same inhalation orpossibly overlapping the same inhalation and a subsequent exhalation.This sequence can all be triggered by an inhalation threshold of airmovement through the breath passage, whereby detection of exhalation isnot relied upon.

[0111] The device includes a counter 243, which displays the number ofbreathing/dispensing cycles so that the prescribed quantity of drug canbe dispensed. However, in other respects, the use of the device isexactly analogous to the that of the mechanical/kink-valve embodiment.

[0112] Referring now to FIG. 11, the dispenser there shown differs fromthat of FIG. 10 in having a single electro-mechanical valve 314, withthe can 307 being a continuous release can. The transducer 321,controller 341, cell 342 and the counter display 343 are physicallyarranged similarly to those of FIG. 10, but the controller isdifferently programmed and includes a timer 3411 circuit. Theprogramming is such that on an inhalation signal being received from thetransducer, the controller causes the valve 314 to open, but only for atime limited to that required for dispensing a dose of drug from thespray nozzle 316 metered by the timer, typically a fraction of a second.On expiry of this period, the controller closes the valve. The openingand closing of the valve for dispensing of the drug occurs entirelywithin the inhalation period and throughout the dispensing, uninhibitedflow of drug from the can occurs, with the handle 331 depressing the canfor opening of its stem valve (not shown). The dispenser continues to beused until the count shown on the counter for a prescribed dosage isreached. Where the user is not being supervised, as of a child by amother, the counter display can be augmented by an audio or visual alarmsuch as an LED. The controller can be provided with keys for setting thenumber of inhalations to be counted before alarming.

[0113] Referring onto FIG. 12, the dispenser there shown differs inhaving a valve (not shown) only in the can 407, which is a metered dosecan. It has a can junction 410, connected to a spray nozzle 416 by adrug duct 411, and a transducer 421 with a controller 441 and a counterdisplay 443. This dispenser has an external power supply for actuating asolenoid 451 on inhalation under control of the controller. The solenoidacts on an arm 431 similar to the handle 331 for depressing the can andreleasing a dose metered by the can's internal valve. Thus on successiveinhalations, up to a prescribed count, the can is depressed and a doseis inhaled.

[0114] The invention is not intended to be restricted to the details ofthe above described embodiments. For instance a valve and actuatorvariant for the dispenser of FIG. 1 is shown in FIG. 13. The valves512,514 there shown are pinch valves having a diaphragm 561 arranged toclose either of a pair of orifices 562,564 under the action of a rocker565 having a pair of pinch fingers 5621,5641. These are normally biasedby leafs 566 to close their orifices and lifted by the rocker 565. Thelatter is pivoted at 522 and actuated by a piston 571 in a cylinder 572,which is open to the breath passage at its respective ends, wherebyinhalation pressure differential across the cylinder drives the pistonin one direction and exhalation drives it the other way. A linkage 573connects the piston to the rocker for actuation of the valve. Such avalve can be electrically actuated by a solenoid in place of the pistonand cylinder.

1. A drug dispensing device for repetitive dispensing on inhalation of adrug released from a pressurised drug source with a can body and adelivery stem, the dispenser comprising: a hollow body having: a wallenclosing a breath passage within the hollow body, an ambient opening tothe breath passage, a patient breathing opening to the breath passage, acan receptor attached to the hollow body for accommodating the can ofthe pressurised drug source, a junction member attached to the hollowbody for connection with the dispensing stem of the pressurised drugsource and leading delivered drug from the dispensing stem, a drugdisperser for dispersing the delivered drug towards the patientbreathing opening, a drug duct from the junction member to the drugdisperser, a breath detector arranged in the breath passage to be actedon by breath passing therethrough, and dose release means operativelyconnected to the breath detector, the dose release means being soarranged that: on inhalation, with the breath detection member detectingsuch, a dose is released into the drug duct and dispersed from the drugdisperser in the patient breathing opening; the arrangement permitting asmall dose of the drug to be repetitively released on each breath by thepatient.
 2. A drug dispensing device for repetitive dispensing oninhalation of a drug released from a pressurised drug source with a canbody and a delivery stem, the dispenser comprising: a hollow bodyhaving: a wall enclosing a breath passage within the hollow body, anambient opening to the breath passage, a patient breathing opening tothe breath passage, a can receptor attached to the hollow body foraccommodating the can of the pressurised drug source, a junction memberattached to the hollow body for connection with the dispensing stem ofthe pressurised drug source and leading delivered drug from thedispensing stem, a drug disperser for dispersing the delivered drugtowards the patient breathing opening, a drug duct from the junctionmember to the drug disperser, a valve in the drug path from thecontainer to the disperser, and a valve actuator operatively connectedto the valve and including a breath detection member arranged in thebreath passage to be acted on by breath passing therethrough, the valveand the actuator being so arranged that: on inhalation, with the breathdetection member detecting such, the valve is opened to allowpressurised drug through a downstream portion of the drug duct anddisperse from the drug disperser in the patient breathing opening; thearrangement permitting a small dose of the drug to be repetitivelyreleased on each breath by the patient.
 3. A drug dispensing device asclaimed in claim 2, including a breathing adapter at the patientbreathing opening for guiding the delivered drug to a patient's airway,the breathing adapter being one of a group comprising a mouthpiece, aface mask, an adapter for a mouthpiece, an adapter for a face mask or aspacer chamber.
 4. A drug dispensing device as claimed in claim 2 orclaim 3, wherein the valve is a dual in line valve arrangement having:an upstream valve, a downstream valve and an intermediate section of thedrug duct between the two valves, the valve and the actuator being soarranged that: on inhalation, with the breath detection member detectingsuch, the downstream valve is opened to allow pressurised drug in thesaid intermediate section to pass through a downstream portion of thedrug duct and disperse from the drug disperser in the patient breathingopening and subsequently the upstream valve is opened to allowpressurised drug to pass from an upstream portion of the drug duct intothe intermediate section; the arrangement permitting a small dose of thedrug metered by the intermediate section to be repetitively releasedtherefrom on each breath by the patient.
 5. A drug dispensing device asclaimed in claim 3, wherein the device is so arranged that it is onexhalation, with the breath detection member detecting such, that theupstream valve is opened for passage of the pressurised drug into theintermediate section.
 6. A drug dispensing device as claimed in claim 3,wherein the device is so arranged that it is during the inhalation orduring overlap between inhalation and exhalation, that the upstreamvalve is opened for passage of the pressurised drug into theintermediate section.
 7. A drug dispensing device as claimed in claim 4,claim 5 or claim 6, wherein the up- and down-stream valves aremechanically linked together, with one being closed when the other isopen and vice versa.
 8. A drug dispensing device as claimed in claim 7,wherein the valves are adapted to be both closed together in amid-position of their mechanical linkage.
 9. A drug dispensing device asclaimed in claim 2 or claim 3, wherein the valve is a single valve andthe valve actuator includes means for closing the valve a predeterminedtime after its opening on inhalation, the arrangement being such thatthe predetermined dose of drug is released during the predeterminedperiod under pressure from drug source.
 10. A drug dispensing device asclaimed in any one of claims 4 to 8, wherein the up- and down-streamvalves are electro-magnetic valves and the breath detection member is atransducer arranged in the breath passage.
 11. A drug dispensing deviceas claimed in claim 9, wherein: the single valve is anelectro-mechanical valve, the breath detection member is a transducerarranged in the breath passage and the valve actuator includes a controlcircuit adapted and arranged to open the valve for a predeterminedperiod on detection of inhalation and then to close the valve.
 12. Adrug dispensing device as claimed in claim 10 or claim 11, wherein thetransducer is a temperature transducer, detecting inhalation by fall intemperature and exhalation by increase in temperature.
 13. A drugdispensing device as claimed in claim 10 or claim 11, wherein thetransducer is a pressure transducer, detecting inhalation by fill instatic pressure or increase in dynamic pressure on the ambient side ofthe transducer (or fall of dynamic pressure on the breathing adapterside) and exhalation by increase in static pressure decrease in dynamicpressure on the ambient side of the transducer (or increase of dynamicpressure on the breathing adapter side).
 14. A drug dispensing device asclaimed in claim 10 or claim 11, wherein the transducer is a flow meterhaving a member movable in the direction of flow through the tube.
 15. Adrug dispensing device as claimed in any one of claims 10 to 14,including a counter arranged to be incremented by indications of breathsgiven by the transducer for counting the number of breaths and drugdispersals controlled by the valve arrangement.
 16. A drug dispensingdevice as claimed in any one of claims 4 to 8, wherein the up- anddown-stream valves are mechanical valves and the breath detection memberis a movable flap or a slidably mounted piston arranged in the breathpassage to be moved in accordance with breath past it and linked to thevalves for their actuation.
 17. A drug dispensing device as claimed inclaim 16, wherein the breath detector is a pivotally mounted flapmovable by the patient's breathing between an inhalation position and anexhalation position and the valves—or their actuation members—arepivotally operated, the flap and the valves or their actuation membersbeing connected together to open the upstream valve (the downstreamvalve being closed) on exhalation and movement of the flap away from thebreathing adapter to fill the intermediate section with drug and openingthe downstream valve (the upstream valve being closed) on inhalation andmovement of the flap towards the breathing adapter to dispense the drug.18. A drug dispensing device as claimed in claim 17, wherein the valvesare kink valves, that is to say valves having flexible tubes which arearranged to kink to close the valve and un-kink to open the valve.
 19. Adrug dispensing device as claimed in claim 18, wherein the up- anddownstream portions of the drug duct are arranged to connect to therespectively opposite ends of the intermediate section via the kinkvalves, the said portions both being to the same side of theintermediate section and describing a squat Δ therewith, and theintermediate section being connected directly to the flap for movementalong the breath passage with the flap.
 20. A drug dispensing device asclaimed in claim 18, wherein the up- and downstream portions of the drugduct are arranged to connect to the respectively opposite ends of theintermediate section via the kink valves, the said portions being onopposite sides of the intermediate section and describing a Z therewith,and the intermediate section being crankedly connected to the flap formovement transversely of the breath passage with movement of the flaptherealong.
 21. A drug dispensing device as claimed in claim 16, whereinthe up- and downstream valves are comprised in a rocker valvearrangement, having up- and downstream pinch vales actuated by a rocker,itself actuated by a piston slidably accommodated in a cylinder open atboth ends to the breath passage for inhalation pressure to move it oneway and exhalation pressure to move it the other way, for correspondingopening of the pinch valves.
 22. A drug dispensing device as claimed inany one of claims 4 to 8, claim 10, claims 12 to 15 as appendant toclaim 10 and claims 16 to 21, wherein the drug duct has a volume betweenthe junction member and the valve corresponding to a plurality of thedoses released on a plurality of inhalations for use with multiple dosesfrom a metered dose pressurised drug source, whereby such pluraldepressions charges the duct with a determined quantity of drug for aplurality of inhalations.
 23. A drug dispenser comprising a dispensingdevice as claimed in any preceding claim in combination with apressurised drug source, the can body being accommodated in the receptorand the delivery stem being connected to the junction member.
 24. A drugdispenser as claimed in claim 23, wherein the pressurised drug sourcehas a metered dose valve for releasing a predetermined drug dose on eachdepression of the delivery stem and the can towards each other.
 25. Adrug dispenser as claimed in claim 16, wherein the pressurised drugsource has a release valve arranged to dispense drug continuously whilstthe can and the delivery stem remain depressed towards each other,whereby the quantity of drug dispensed whilst the can is depressedcorresponds to the quantity of drug per inhalation times the number ofinhalations.
 26. A drug dispensing device for repetitive dispensing oninhalation of a drug released from a pressurised drug source with a canbody, metered dose release drug release valve and a delivery stem, thedispenser comprising: a hollow body having: a wall enclosing a breathpassage within the hollow body, an ambient opening to the breathpassage, a patient breathing opening to the breath passage, a canreceptor attached to the hollow body for accommodating the can of thepressurised drug source, a junction member attached to the hollow bodyfor connection with the dispensing stem of the pressurised drug sourceand leading delivered drug from the dispensing stem, a drug disperserfor dispersing the delivered drug towards the patient breathing opening,a drug duct from the junction member to the drug disperser, and a breathdetection transducer arranged in the breath passage to be acted on bybreath passing therethrough, a can actuator operatively connected to thebody for moving the can towards the junction member, the can actuatorbeing so arranged that: on inhalation, with the breath detection memberdetecting such, the can is moved to operate its metered dose valve forallowing pressurised drug to flow to the drug disperser and to dispersefrom the drug disperser in the patient breathing opening; thearrangement permitting a small dose of the drug to be repetitivelyreleased on each breath by the patient.
 27. A drug dispensing device asclaimed in claim 26, wherein the transducer is a temperature transducer,detecting inhalation by fall in temperature and exhalation by increasein temperature.
 28. A drug dispensing device as claimed in claim 26,wherein the transducer is a pressure transducer, detecting inhalation byfall in static pressure or increase in dynamic pressure on the ambientside of the transducer (or fall of dynamic pressure on the breathingadapter side) and exhalation by increase in static pressure decrease indynamic pressure on the ambient side of the transducer (or increase ofdynamic pressure on the breathing adapter side).
 29. A drug dispensingdevice as claimed in claim 26, wherein the transducer is a flow meterhaving a member movable in the direction of flow through the tube.
 30. Adrug dispensing device as claimed in any one of claims 25 to 28,including a counter arranged to be incremented by indications of breathsgiven by the transducer for counting the number of breaths and drugdispersals controlled by the valve arrangement.
 31. A drug dispensercomprising a dispensing device as claimed in any one of claims 26 to 30in combination a pressurised drug source having a metered dose valve,the can body being accommodated in the receptor, arranged to be acted onby the can actuator and the delivery stem being connected to thejunction member.